Steel reinforcing bars, commonly referred to as rebars, have long been used to improve the strength and durability of a wide range of concrete structures such as footings, foundations, walkways, platforms, support beams, building frames and the like, making reinforced concrete one of the most common building material used in the construction industry. The use of rebar in these structures involves the construction and securing of rebar grids at various heights above the bottom of a concrete form or granular base. Rebar support devices are used to position and hold rebar members in the formation of said reinforcing grids and therefore play an important role in the production of reinforced concrete structures.
Rebar support devices may be broadly grouped into three principal categories: 1. Unitary devices providing one or more levels of rebar support and designed for placement on a granular surface, such as a gravel bed. 2. Unitary devices providing one or more levels of rebar support and designed for placement on a solid surface, such as the bottom of a concrete form. 3. Multiple component devices which provide one or more levels of rebar support and also the means to configure the component parts thereof to permit use on either a granular surface or a solid surface in the construction of rebar grids.
It is appreciated that numerous rebar support devices are known in the art. Examples are U.S. Pat. No. 3,673,753 to Anderson, U.S. Pat. No. 6,354,054 to Verelli and Verelli, U.S. Pat. No. 6,684,594 to Sorkin, U.S. Pat. No. 7,451,580 to Kelly et al. and U.S. Pat. No. 7,870,702 to McKay.
Exemplary rebar support devices providing one or more levels of rebar support and designed for placement on a granular surface, such as a gravel bed, may be found in U.S. Pat. Nos. 3,673,753, 6,684,594 and 7,870,702, the disclosure provided in U.S. Pat. No. 3,673,753, being representative of this category. In U.S. Pat. No. 3,673,753, a concrete rebar support device is disclosed comprising a unitary base with upright pedestal, said pedestal portion having lower and upper clamping means at its apex, defining first and second intersecting passageways disposed normal to each other, for simultaneously receiving rebar members therein. Resilient detents and hook means incorporated in said lower and upper clamping means assist in keeping rebars in place once positioned.
In U.S. Pat. No. 6,354,054, there is disclosed a unitary rebar chair comprising a tower with four legs between which there are defined two intersecting passages for simultaneously receiving the intersecting portions of two rebars normal to each other, said tower further having a saddle formation at its apex to accept one or two additional rebar members to form a multilevel rebar grid. U.S. Pat. No. 6,354,054 is exemplary of unitary devices providing one or more levels of rebar support and designed for placement on a solid surface, such as the bottom of a concrete form.
U.S. Pat. No. 7,451,580, is exemplary of a multiple component device providing one or more levels of rebar support and means to configure the component parts thereof to permit use on either a solid or granular surface in the construction of rebar grids. In this disclosure a rebar chair comprises a first component tower with rebar cradle means at its top surface and four legs which diverge down from the top surface, terminating in tapered feet for minimal contact with a concrete form. A second component base, described therein as a sand plate and also known in the art as a bearing plate, has radially extending slots formed to engage the feet of first component tower structure, the combination first component tower and second component base allowing the assembly thereof to be used on a granular surface.
In summary, the prior art has evolved to provide varied and effective means for the positioning and support of rebar members in the construction of rebar grids in reinforced concrete structures. However, what has not been adequately addressed is the need for a simple and effective rebar support system comprising a minimal number of component parts, each component part individually providing means for rebar support in specific applications, the cooperative combination of the component parts thereof further extending the functionality and range of applications in the formation of rebar grids on different types of surfaces.